Get Enzymes And Cellular Regulation Pogil Key

At pH values above 7, lipase denatures and aggregates when heated at temperatures above 45 degrees C. However, at pH below 6 lipase denatures upon heating but the activity and its native structure is completely recovered upon cooling.

Thus too much heat can cause the rate of an enzyme-catalyzed reaction to decrease because the enzyme or substrate becomes denatured and inactive.

Name the two enzymes illustrated in Model 1. pepsin and lipase 2. Consider the information provided in the Why? box and in Model 1 about these proteins.

Enzymes aid in cell regulation by catalyzing reactions needed to establish homeostasis. The concentrations of certain substances in cells need to be maintained in a narrow range.

Above a certain temperature, activity begins to decline because the enzyme begins to denature. The rate of chemical reactions therefore increases with temperature but then decreases as enzymes denature.

This optimal temperature is usually around human body temperature (37.5 oC) for the enzymes in human cells. Above this temperature the enzyme structure begins to break down (denature) since at higher temperatures intra- and intermolecular bonds are broken as the enzyme molecules gain even more kinetic energy.

As with many chemical reactions, the rate of an enzyme-catalysed reaction increases as the temperature increases. However, at high temperatures the rate decreases again because the enzyme becomes denatured and can no longer function.